Biochemical Test

Biochemical tests are the tests that are performed on different bacteria for their identification on the basis of their biochemical activities towards different biochemical compounds.

  • Biochemical tests are one of the traditional methods for the identification of microorganisms, usually performed with phenotypic identification.
  • For many years these methods were employed extensively, and they continue to be used nowadays, especially in some laboratory routines where a particular type of microorganism has to be identified rapidly.
  • The ability of microorganisms to utilize certain biomolecules, resulting in useful organic compounds for themselves forms the basis of various biochemical tests.
  • Biochemical tests are of different types, where the identification or distinction between different microorganisms is made on various bases.
  • One of the traditional methods commonly used is a simple visual detection of the growth of the organism in the presence of essential nutrients by increased turbidity in the liquid medium.
  • In other tests, however, the results are based on the change in color of the medium as a result of the change in the pH of the medium.
  • Microorganisms can be classified into different groups on the basis of their reaction to such tests. Some tests even allow the distinction of microorganisms to the species level.
  • Biochemical tests are thus, essential as they are inexpensive and relatively simple to perform.
  • The physiology of bacteria and other microorganisms differs from one another, which allows for the differentiation of such microorganisms.
  • Biochemical tests, however, have some disadvantages. Despite being inexpensive and allowing both quantitative and qualitative information about the diversity of microorganisms present in a sample, these methods are laborious and time-consuming, and results are only observed after several days.
  • In some cases, false positives are obtained, especially when considering similar microbial species.

Biochemical Test of Clostridium perfringens

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Biochemical Test of Clostridium perfringens

Basic Characteristics Properties (Clostridium perfringens) 20% Bile Positive (+ve) Capsule Positive (+ve) Catalase Negative (-ve) Flagella Negative (-ve) Gas Positive (+ve) Gelatin Hydrolysis Positive (+ve) Gram Staining Gram-positive Hemolysis Positive … Read more

Biochemical Test of Brucella melitensis

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Biochemical Test of Brucella melitensis

Basic Characteristics Properties (B. melitensis) Capsule Negative (-ve) Catalase Positive(+ve) Flagella Negative (-ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Gram Negative (-ve) H2S Negative (-ve) Hemolysis Negative (-ve) Indole Negative … Read more

Biochemical Test of Bifidobacterium bifidum

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Biochemical Test of Bifidobacterium bifidum

Basic Characteristics Properties (Bifidobacterium bifidum) 2% Bile Salt Positive (+ve) Capsule Negative (-ve) Catalase Negative (-ve) Flagella Negative (-ve) Gas Negative (-ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Gram-Positive (+ve) … Read more

Biochemical Test of Streptococcus pyogenes

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Biochemical Test of Streptococcus pyogenes

Biochemical Test of Streptococcus pyogenes Characteristics Properties (Streptococcus pyogenes) CAMP Negative (-ve) Capsule Capsulated Catalase Negative (-ve) Gram Staining Positive (+ve) Hemolysis Beta Motility Non-Motile OF (Oxidative-Fermentative) Fac. Anaerobes PYR … Read more

Biochemical Test of Salmonella Typhi

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Biochemical Test of Salmonella Typhi

Biochemical Test of Salmonella Typhi Characteristics Salmonella Typhi Capsule Negative (-ve) Catalase Positive (+ve) Citrate Negative (-ve) Flagella Positive (+ve) Gas Negative (-ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Negative (-ve) … Read more

Biochemical Test of Acinetobacter baumannii

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Biochemical Test of Acinetobacter baumannii

Image Source: BioCote Some of the characteristics are as follows: Basic Characteristics Properties (Acinetobacter baumannii) Bile Solubility Negative (-ve) Capsule Capsulated Catalase Positive (+ve) Citrate Positive (+ve) Coagulase Negative (-ve) … Read more

Biochemical Test of Shigella flexneri

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Biochemical Test of Shigella flexneri

Biochemical Test of Shigella flexneri ­Basic Characteristics Properties (Shigella flexneri) Catalase Positive (+ve) Citrate Negative (-ve) Gas Positive (+ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Negative (-ve) Growth in KCN … Read more

Biochemical Test of Bacteroides fragilis

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Biochemical Test of Bacteroides fragilis

Basic Characteristics Properties (Bacteroides fragilis) Capsule Positive (+ve) Catalase Positive (+ve) Flagella Negative (-ve) Gelatin Hydrolysis Weakly Positive (+ve) Gram Staining Gram-negative (-ve) Growth in Bile (20%) Positive (+ve) Hemolysis … Read more

Biochemical Test of Bacillus subtilis

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Biochemical Test of Bacillus subtilis

Biochemical Test of Bacillus subtilis ­Basic Characteristics Properties (Bacillus subtilis) Catalase Positive (+ve) Citrate Positive (+ve) Flagella Flagellated Gas Negative (-ve) Gelatin Hydrolysis Positive (+ve) Gram Staining Gram Positive (+ve) … Read more